Method of manufacturing fatty acids



\ invention above,

latented Dec. 28, 1926;

UNITED STATES ADOLF WELTER, 0F KREFELD-IBIHIEIINHAFIEIN', GERMANY.

METHOD OF MANUFACTURING FATTY ACIDS.

No Drawing. Application filed October 4, 1924, Serial No. 741,764, and in Germany October 23, 1823.

heating mixture containing neutral fats with steam at a maximum pressure of 8 atmospheres and in the presence of'any splitting agentheretofore considered suitable, for instance, magnesia, lime, zinc oxide, tin or the like, splitting to about to removing the glycerine water and thereupon completing splitting. at a pressure between 6 to 7 atm. underaddition of small quantities of a suitable alkali and water, as which may be, for instance, caustic alkali, soda, potash, sodium or potassium water glass, or an alkaline soap. Through the addition of the said substances, the fat with the water, so that the subsequent splitting is effected at a pressure of 6 to 7 atmospheres and at temperatures between 160 to 170 centigrade and above all exceeds 99%.

It has already been proposed to split fats and oils in two stages, by first heating the primary materials with steam at a pressure of 6 to 7 atmospheres in the presence of finely divided metals, metallic oxides or metallic oxide salts of fatty acids and water until the saponification became slower and the glycerine had reached its highest state of concentration. The glycerine water was thereupon drawn off and the saponification of the residue of fatty product was completed. The process according to the present difiers from this older process in this, that in the second part of the process an alkaline splitting agent such as caustic alkali is used, while formerly in both parts of the process zinc dust or the like was used. It has already been proposed to use an alkali in the splitting of fats, but only by carrying out the whole process in one stage Hence the novelty of the present invention consists in the combination of two known processes, viz, the division of the szalittingprocess into two stages and the use 0 an alkali as a splltting agent, the latter in the second stage, while in the first stage, in which the splitting need not be carried so far, any suitable agent, which may of course be an alkal may be used. v

The new process makes it possible to work at a far lower pressure than was hitherto necessary. For the reason that, as mentioned under the present invention splitting to more than 99% can be obtained at 6 to forms a good emulsionv atm. to get a complete splittin by treating oils and fats with any suita 1e splitting agent under pressure in a pressure vessel.

Hitherto it was always necessary to'decide whether to use a pressure snfficient for effect ng a complete 98 to splitting entailing the disadvantage of considerable disintegrations, or to be satisfied with an incomplete splitting. It was not possible to get round these difiiculties by the first named process.

The present invention may be applied with v advantage to' all vegetable and animal kinds of oils and fats, such as cocoanut oil, palm kernel 011, Walnut oil, tallow and the like. Tllie following example refers to cocoanut o1 It is to be remarked that the problem of how much watervis to be added in the first stage of the process depends on the heat insulation of the pressure vat. If this insulat10n 1s very good, a small quantity of water for instance about 10 to 20% ofthe oil must be added. If, however, the insulation is poor, no water need be added,,since in such case so much steamis recipitated in the pressure vat that it supplies the needed quantity of water.

Ewample.

8000 kg. cocoanut oil having a saponification number of 255 are split in a copper autoclave of 12 cubic meters capacity at 6-7 atmospheres with an addition of 25 kg. zinc dust for from 6 to 7 hours. It is not necessary to add water, because in the autoclave, which is not isolated, so much of the steam which passes through is condensed with a sufiicient quantity of water is present to act as a hydroly zing agent. After letting the contents of the autoclave remain quiescent for two hours the lower layer of glycerine water and a layer superposed on' the lower layer consisting of water and impurities such as lime and albuminous substances. is

6 hours at from 6 to 7 atmospheres. While after the first splitting the acidity number only rises to from 230 to 240, it amounts to from 260 to 265 after the second splitting. A determination of the glycerine after thorough washing proves that the splitting has been carried to over 99%.

It should be noted that the most suitable alkalies for the purpose are caustic alkali, soda, potash. In place of these alkalies, equivalent quantities of their soaps or their soluble silicates may be used.

True enough, it is not new'to operate selectively with anyone of the here mentioned splitting mediums, that is to split into glycerin and fatty acids, fats of vegetable and animal origin with or without pressure and temperatures corresponding to the respective pressures, that is in the presence of steam and of alkali in any form or combina tion or of magnesia,lime, zinc oxide, tin or the like. However in the past only 92% of the theoretic yield has been obtained.

It has also been proposed to effect this splitting-except when'alkali is usedas the splitting medium--in two stages, the glycerin-water formed with the impurities contained therein, being removed in between the two stages. However, in such cases only 96% yield was obtained, which was in pract1ce too little. Applicant has now found that during the second stage of the process it is not permissible to use magnesia, lime, zinc oxide, tin or the like, but only alkali in a solid form or dissolved in water. This has never been proposed before, nobody having thought of working in two stages, when alkali is employed, nor of omitting in the second stage any other splitting medium used in the first stage and replacing it by alkaline compounds.

What I claim is A process for the manufacture of highly sphtfatty acids in two stages consisting in first splitting neutral fats to a degree of 85 to 95 thereof by means of any suitable splitting agent and steam .under a pressure of about 6 to 7 atmospheres and then after removing the glycerine, water and impurities insoluble in the oil completing the splitting to more than 99% by means of an alkaline splitting agent and steam under a pressure of about 6 to 7 atmospheres.

In testimony whereof I have signed my name to this specification.

ADOLF WELTER. 

